ISSN:
1573-8744
Keywords:
methotrexate
;
dihydrofolate reductase
;
enzyme synthesis
;
enzyme degradation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Mice were injected with methotrexate (MTX) (10 mg/kg) and folinic acid (30 mg/kg), the latter being used as a precaution against toxicity. The disappearance of MTX and the appearance of free dihydrofolate reductase were followed with time in Walker 256 carcinoma, Murphy-Sturm lymphosarcoma, and intestinal mucosa of the rat and in the intestine, liver, kidney, and P388 ascites leukemia in mice. The rate of loss of MTX from the rapidly growing tissues seems to reflect the growth rate of these tissues, since MTX is not lost from living cells. The rate of appearance of free enzyme in these rapidly growing tissues suggests that the rate of degradation is small relative to the tissue growth rate. In mouse kidney and liver, on the other hand, the rate of enzyme degradation is much faster than the negligible growth rate of these tissues. The results in mouse liver probably indicate that the MTX- bound enzyme is 1.5 times more stable to decay than free enzyme.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01066922
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